示例：Socket應用之簡易聊天室

在實際應用中，Server老是在指定的端口上監聽是否有Client請求，一旦監聽到Client請求，Server就會啓動一個線程來響應該請求，而Server自己在啓動完線程以後立刻又進入監聽狀態。

示例：Socket應用之簡易聊天室

當一個Client鏈接Server以後，Server將向全部Client發送一個消息，這就須要Server和Client都一直處於監聽狀態。

在Server，1. 經過一個List來存儲全部鏈接進來的Socket 2. 爲每一個client開啓了一個線程來響應請求。

服務端程序

public class Server {

  private static final int SERVER_PORT = 54321;

  private static List<Socket> mClientList = new ArrayList<Socket>();

  private ExecutorService mExecutorService;

  private ServerSocket mServerSocket;

  public Server () {

    try {

      mServerSocket = new ServerSocket(SERVER_PORT);

      mExecutorService = Executors.newCachedThreadPool();

      socket client = null;

      while(true) {

        client = mServerSocket.accept();

        mClientList.add(client);

        mExecutorService.execute(new ThreadServer(client));

      }

    } catch (IOException e) { }

  }

  // 爲每一個client獨立開啓一個線程。

  static class ThreadServer implements Runnable {

    private Socket mSocket;

    private BufferedReader mBufferedReader;

    private PrintWriter mPrintWriter;

    private String mStrMsg;

    public ThreadServer(Socket socket) throw IOException {

      mSocket = socket;

      mBufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream));

      mStrMsg = 「user(」+mSocket.getInetAddress()+」) come, total client count: 」 + mClientList.size();

      sendMessage();

    }

    public void run() {

      try {

        while((mStrMsg = mBufferedReader.readLine())!=null){

          if(mStrMsg.trim().equals(「exit」)) {

            // 當一個client退出時

            mClientList.remove(mSocket);

            mBufferedReader.close();

            mPrintWriter.close();

            mStrMsg = 「user(」+mSocket.getInetAddress()+」) exit, total client count: 」 + mClientList.size();

            mSocket.close();

            sendMessage();

            break;

          } else {

            mStrMsg = mSocket.getInetAddress() + 「:」+ mStrMsg;

            sendMessage();

          } // else

        } // while

      }  catch(IOException e) { }

    }

    // 發送信息給全部client

    private void sendMessage() throws IOException {

      for(Socket socket : mClientList) {

        mPrintWriter = new PrintWriter(client.getOutputStream(), true);

        mPrintWriter.println(mStrMsg);

      }

    }

  }

}

 

客戶端程序

// android client app

在onCreate方法中

// 點擊「登陸」鏈接服務器

mSocket = new Socket(SERVER_IP, SERVER_PORT);

// 取得輸入輸出流

mBufferedReader = new BufferedReader(new InputStreamReader(mSocket.getInputStream()));

mPrintWriter = new PrintWriter(mSocket.getOutputStream(), true);

// 點擊「發送消息」

String msg = mMsgBox.getText().toString();

mPrintWriter.print(msg);

mPrintWriter.flush();

// 開啓線程監聽服務器發來的消息

new Thread(mRunnable).start();

 

// 監聽Server發來消息的線程

private Runnable mRunnable = new Runnable(){

  public void run() {

    while(true) {

      try {

        if((mStrMsg = mBufferedReader.readLine())!=null) {

          mStrMsg += 「\n」;

          mHandler.sendMessage(mHandler.obtainMessage());

        }

      } catch(Exception e) { }

    }

  }

};

 

Handler mHandler = new Hander(){

  super.handleMessage(msg);

  try {

    mMsgLabel.append(mstrMsg);

  } catch(Exception e) { }

}